1. Technical Field
The present invention relates to a semiconductor device and a method for manufacturing the same, and more particularly, to a semiconductor device and a method for manufacturing the same which can suppress an HEIP (hot electron-induced punch-through) phenomenon in a highly integrated semiconductor device.
2. Related Art
As a semiconductor device is highly integrated, a channel length gradually decreases, and the threshold voltage of a transistor is gradually reduced.
Due to such narrow effects an HEIP (hot electron-induced punch-through) phenomenon occurs, specifically, in a word line formed in the peripheral circuit region of a semiconductor integrated circuit. That is to say, additional electrons are produced in a portion where an active region and a word line overlap with each other, and as these electrons are trapped on an interface between the active region overlapping with the word line and an isolation layer, leakage current is generated along the interface of the active region.
The HEIP phenomenon causes a result that the channel length further decreases and the threshold voltage is further reduced. In a worse case, unwanted turn-on of a transistor may be caused.
Therefore, as off-leakage current increases in a standby state, problems are caused in that not only power consumption increases, but also an operating speed may decrease or a malfunction may result.
In order to solve these problems, while an attempt has been made in which doping concentrations of source and drain areas are increased in an effort to suppress the HEIP phenomenon, difficulties still exist in completely suppressing the HEIP phenomenon.